My brother gifted me 10x 50AE rounds he found in a plastic baggy at a pawn shop on one of his business trips two years ago. I stashed them away since then and found them again. Didnt pay much attention until now and realized they're IMI headstamped. Primers seem a tad smaller than Hornady and Armscorp 50 ae I have and these have red sealant on them. Can't seem to find a whole lot about these particular rounds. What's the details on these? Okay to shoot?  

I'd imagine those are the "Samson" 300gr JSP loads.

Yep, those came in boxes labeled "sampson".
They are factory IMI loads. The read sealant is a good giveaway they are factory loads and not someone's reloads.
Excellent ammo, full power, and really good brass.
If for some reason you do not want the brass after you shoot it, let me know and I will take it.
IMI is the only 50 AE brass I have.

Good to know, appreciate the insight on these!

Cartridges…. cartridge case.
I read that the base of a bullet would be marked, that would be highly unusual.
But used headstamp, kudos.